Operate on a selection of variables

The variants suffixed with _if, _at or _all apply an
expression (sometimes several) to all variables within a specified
subset. This subset can contain all variables (_all variants), a
vars() selection (_at variants), or variables selected with a
predicate (_if variants).

Arguments

.tbl

A tbl object.

.funs

List of function calls generated by funs(), or a
character vector of function names, or simply a function.

Bare formulas are passed to rlang::as_function() to create
purrr-style lambda functions. Note that these lambda prevent
hybrid evaluation from happening and it is thus more efficient to
supply functions like mean() directly rather than in a
lambda-formula.

.vars

A list of columns generated by vars(),
a character vector of column names, a numeric vector of column
positions, or NULL.

.predicate

A predicate function to be applied to the columns
or a logical vector. The variables for which .predicate is or
returns TRUE are selected. This argument is passed to
rlang::as_function() and thus supports quosure-style lambda
functions and strings representing function names.

...

Additional arguments for the function calls in
.funs. These are evaluated only once, with tidy
dots support.

There are three kinds of scoped variants. They differ in the scope
of the variable selection on which operations are applied:

Verbs suffixed with _all() apply an operation on all variables.

Verbs suffixed with _at() apply an operation on a subset of
variables specified with the quoting function vars(). This
quoting function accepts tidyselect::vars_select() helpers like
starts_with(). Instead of a vars() selection, you can also
supply an integerish vector of column
positions or a character vector of column names.

Verbs suffixed with _if() apply an operation on the subset of
variables for which a predicate function returns TRUE. Instead
of a predicate function, you can also supply a logical vector.